Jack and needle actuator for a circular knitting machine

ABSTRACT

A selected jack and needle of a circular knitting machine are rapidly and positively positioned into and maintained in their operative knitting or non-knitting positions during the associated knitting cycle in response to a momentary control pulse applied to an actuating electromagnet. A magnetizable spring member is drivingly connected to the jack and is mechanically biased into one of two extreme positions corresponding to the knitting or non-knitting positions of the jack. When the momentary control pulse is applied, the actuating electromagnet initially overcomes the force of a permanent magnet which is maintaining the spring in the mechanically biased condition and thereby switches the spring into an opposite position. At the conclusion of the control pulse the spring is prevented from returning to its bias position until the end of the associated knitting cycle by a cam member.

[451 May28, 1974 i 1 JACK AND NEEDLE ACTUATOR FOR A CIRCULAR KNITTING MACHINE [75] Inventor: Werner Engelfried, Sindelfingen,

Germany [73] Assignee: C. Terrot & Soehne, Stuttgart,

Germany [22] Filed: Sept. 20, 1971 [21] Appl. No.: 182,082

Related US. Application Data [63] Continuation-in-part of Ser. No. 864,402, on 7,

1969, abandoned.

753,211 7/1956 Great Britain 66/50 R 1,143,887 2/1969 Great Britain 66/50 R 1,160,100 7/1969 Great Britain 66/50 R 466,888 2/l969 Switzerland..l 66/50 R Primary Examiner-Wm. Carter Reynolds [57] ABSTRACT A selected jack and needle of a circular knitting machine are rapidly and positively positioned into and maintained in their operative knitting or non-knitting positions during the associated knitting cycle in response to a momentary control pulse applied to an actuating electromagnet. A magnetizable spring member is drivingly connected to the jack and is mechanically biased into one of two extreme positions corresponding to the knitting or non-knitting positions of the jack. When the momentary control pulse is applied, the actuating electromagnet initially overcomes the force of a permanent magnet which is maintaining the spring in the mechanically biased condition and thereby switches the spring into an opposite position. At the conclusion of the control pulse the spring is prevented from returning to its bias position until the 4 Claims,- 17 Drawing Figures PATENTEDm 28 m4 sum 01 or 10 FIG.

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JACK AND NEEDLE ACTUATOR FOR A CIRCULAR KNITTING MACHINE CROSS-REFERENCE TO RELATED APPLICATION BACKGROUND OF THE INVENTION In the operation of circular knitting machines, it is common to employ actuators for raising a selected jack and needle into operative knitting positions in response to a control pulse generated, e.g., when a multicolor scanned pattern sample exhibits a color corresponding to the machine knitting system to which the jack and needle are assigned.

While this-arrangement is generally sound, it is found that the control pulses must be maintained over the entire knitting interval of the selected jack and needle in order to assure their proper actuation and operation over this interval. Also, the high average current through the coil of the electromagnet over this interval requires the coil to be made of relatively heavy wire.

In a known arrangement the needle actuating jacks are not directly connected to the needles. The jacks are directly actuated by magnetic forces in the needle selection range. The current input forproducing. these magnetic forces are, however, several times larger than the permissible current load for the wiring of the associated electromagnet, which produces the aforementioned magnetic forces, so that a wiring of reduced cross-section can not be used. Since the jacks are not directly connected to the knitting needles, this known arrangement frequently malfunctions and has been found unsatisfactory.

In another known arrangement the needle actuating SUMMARY OF THE INVENTION Such disadvantages may be overcome with an illustrative arrangement in accordance with the invention in which a magnetizable spring member is drivingly coupled to a selected jack and needle. The spring is biased by a suitable cam member into a selectable one of first and second positions corresponding respectively to knitting and non-knitting positions of the jack and needle and selectively maintained in this biased condition by a permanent magnet. When the jack is selected for operation, an actuating electromagnet responds to a momentary control pulse, e.g., of duration much shorter than the knitting cycle of the jack, for initially overcoming the magnetic bias to permit the spring to move into the second position. When the control pulse terminates the permanent magnet biasing means are restored. A separate cam arrangement is provided to maintain the spring in the second position for the remainder of the knitting cycle. The short duration of the control pulse is produced by a current, which is several times larger than the permissible maximum sustained current which said coil of wire can tolerate and therefore permits the use of smaller wire on the coil of the electromagnet.

BRIEF DESCRIPTION OF THE DRAWING The nature of the invention and its advantages will appear more fully from the following detailed description taken in conjunction with the appended drawing, in which:

FIG. 1 is a schematic elevational, cross sectional view of the device of this invention showing also a portion of the cylinder of a circular knitting machine comprising needles and jacks;

FIG. I--1 is a schematic elevationahcross sectional view similar to FIG. 1 showing the jack and spring of the device of the invention in the position indicated by line 1-1 1-1 of FIG. 3; a

FIG. 12 is a schematic elevational, cross-sectional view similar to FIG. 1 showing the jack and the spring of the device of the invent-ion in by line 1-2 l2 of FIG. 3;

FIG. 1-3 is a schematic elevational,cross-sectional view similar to FIG. 1 showing-the jack and the spring of the device of the invention in the position indicated by line [-3 I-3 of FIG. 3;

FIG. l4 is a schematic elevational, cross-sectional view similar to FIG. 1 showing the jack and the spring of the device of the invention in the position indicated byline l4 l-4 of FIG. 3;

FIG. 1-5 is a schematic elevational, cross-sectional view similar to FIG. 1 showing the jack and the spring of the device of the invention in the position indicated by line 1-5' 1-5 of FIG. 3; i.

FIG. l"6 is'a schematic elevational, cross-sectional view similar to FIG. 1 showing the jack and the spring of the device of the invention in the position indicated by line 1-6 l-6 of FIG. 3;

FIG. 1-7 is a schematic elevational, cross-sectional view similar'to FIG. 1 showing the jack and the spring of the device of the invention in theposition indicated by line I-7 1-7 of FIG. 3;

FIG. 1-8 is a schematic elevational, cross-sectional view similar to FIG. 1 showing the jack and the spring of the device of the invention in the position indicated by line l8 l8 of FIG. 3;

FIG. 1-1' is a schematic elevational, cross-sectional view similar to FIG. 1 showing the jack and the spring of the device of the invention in the position indicated v by line l1-ll' of FIG. 4:

FIG. 12' is a schematic elevational, cross-sectional view similar to- FIG. 1 showing the jack and the spring of the device of the invention in the position indicated by line 12 12' of FIG. 4:

FIG. l6' is a schematic elevational, cross-sectional view similar to FIG. 1 showing the jackand the spring of the device of the invention in the position indicated by line l'-6' l-6' of FIG. 4; I

FIG. 1-7' is a schematic elevational, cross-sectional view similar to FIG. 1 showing the jack and the spring of the device of the invention in the position indicated by line l-7 l-7 of FIG. 4;

FIG. l8' is a schematic elevational, cross-sectional view similar to FIG. 1 showing the jack and the spring of the device of the invention in the position indicated by line 1 -8' -18' of FIG. 4;

the position indicated FIG. 2 is a view along line II-II of FIG. 1.

FIG. 3 is a plan view of the device of this invention wherein the springs of the jacks are indicated by circlesand the path traversed by these springs is indicated in a solid line when the needle jacks and associated knitting needles are traversing the knitting path;

FIG. 4 is a plan view of the device of this invention wherein the springs of the jacks are indicated by circles and the path traversed by these springs is indicated in a solid line when the needle jacks and associated knitting needles are traversing the non-knitting path;

DETAILED DESCRIPTION Referring now in more detail to the drawing, there is illustrated in FIG. I a portion of the cylinder 1 of a circular knitting machine with a needle 4. The cylinder is provided in a known manner with grooves 2 in which the needles are guided. The walls of the grooves in the lower portion of the cylinder are formed by added partitions 20. Each one of the needles 4 has at its lower end a male hinge member 4a which is pivotally connected by means of'a female hinge member 3b at theupper Y end of theassoc-iated jack 3 to'the latter. Due to these pivot connections the jacks 3 can effect angular movements with respect to the needles 4 about the hinge connection 4a, 3b." The jacks 4 are illustrated in FIG.

I in their starting position; which position they occupy in the momentof the selection and in which position they bear against-a conventional stop ring R which limits an outward pivoting of the jacks 3. The cross-section of'the'spring 6 amounts to only a small fraction of the cross-section of jack 3, as is clearly evident in FIG. I.

' In its relaxed condition, the spring extends in the direction of the length of the jack. The selecting device according to the invention places the jacks selectively into oneof two well defined positions, namely into an inoperative and an operative position. In one of these two positions (which could be eitherinoperative or operative as will be explained herein below) the jacks are sunk with their butt 3a in the grooves, and in the other position butt 3a penetrates sufficiently deep into the cam plate 5 in order to be engaged by the cams 5a.

The selecting device of this invention which effects the positioningof the jacks 3 into one of the afore described positions is mounted on a frame 10 of the circular knitting machine. The selecting device comprises a circumferential carrying-member 9 onto which there are mounted a plurality of permanent magnets 7 and electromagnets 8. A second circumferential carrying member 9a is provided opposite the carrying member 9 and supports pairs of cams 1.1 and 12 thereon opposite each arrangement of a permanent magnet 7 and an elect'romagnet 8. There is firmly secured to the bottom end of each jack 3 a-flexible magnetizable spring member 6 which is instrumental in placing the associated jack 3 into one of the afore described positions corresponding respectively to a knitting position" and a non-knitting position".

' KNITTING POSITION The jacks, 3 are pivoted into the knitting position via the springs 6 by meansof a cam member 12 which biases the springs 6 (as shown in FIG. 1) prior to their arrival to a position opposite the permanent magnet 7. The spring 6-is maintained in this mechanically biased position by meansof the permanent magnet 7 within the selecting-range of travel of the jacks 3. The path of travel of the springs 6 are shown by the arrows in FIG. 2. Thus there is illustrated in FIG. 1 a needle for an associated jack 3 shown in their knitting position. In FIG. 1 the parts are shown at that instant in which the spring 6 has been bent to theright by cam 11 and is being attracted by the permanent magnet 7. After the spring 6 has moved in its travel past the axis of the permanent magnet 7 it continues to be maintained in its mechanically biased condition by means of a second cam member 11. Thus in the afore described operation the jacks 3 are not pivoted with respect to the needles 4 after the positioning of the former by means of the cam members 12. The jacks are, of course, actuated in a known manner by the actuating cams 5 which coact with the butts 3a.

NON-KNITTING POSITION mitting the spring 6 to snap back. Thespring 6 therefore moves along the path indicated by the" dotted arrow in FIG. 2. Due'to the snapping back of the spring 6 and 'moving along the path of the dotted arrow the jacks'3 undergo a pivotal movement withrespect to the needles 4 so that the butts 3a no longer are coacting with the cam members 5a, that is no longer come into contact with these cam members. The springs 6 in effect move along the inner surface (with respect to the axis of the circular knitting machine) of the cam members 11 as shown in FIG. 2. Since the butts 3a no longer coact with the cam members 5a the jacks 3 and associated needles '4 are not moved upwardly by means of the cam members 5a and, consequently, the associated needles 4 do not move into the operative or knitting position.

It is, of course, possible to construct the afore described arrangementin such a way that the pivotal movementof. the jacks would produce the reverse of what has been described above. In such acase a pivotal movement of the jacks with respect to the needles The use of cam 11 to maintain a selection enables the use of very short term amperage in coil 8.

The invention is illustrated and described with a reference to a plurality of preferred embodiments thereof and it is to be understood that it is in no way limited to said plurality of embodiments but is capable of numerous modifications according to the appended claims.

What is claimed is:

1. In a circular knitting machine having a rotating cylinder and stationary selection cams, an arrangement for selectively positioning elongated jacks and needles into one of two defined positions so that said jacks may selectively be actuated by cams in a selection range through which said jacks are travelling in response to a control pulse whose duration is short compared to the knitting cycle of the jack and needle, comprising in combination:

a magnetizable leaf spring member secured to the lower end of each jack and extending in the direction of the length of the jack when in relaxed condition, the cross-section of the leaf spring amounting to only a small fraction of the cross-section of the jack,

the upper end of each jack being pivotally connected to the lower end of an associated knitting needle,

first cam means adapted to mechanically bias at each of said magnetizable spring members prior to its arrival at said selection range,

stationary magnetic biasing means disposed along said selection range; and being adapted to maintain each of said magnetizable spring members in said mechanically biased condition to cause a coaction between jack and cams of the circular knitting machine;

and stationary electromagnetic means disposed along said selection range for selectively counteracting said stationary magnetic biasing means in response to a control pulse to at least partially dissipate the force produced by said stationary magnetic biasing means to allow such selected spring member to move to a mechanically unbiased condition and thereby produce a pivot movement between the jack and needle associated with each selected spring member which causes an interruption of coaction between the respective jack and cams of the circular knitting machine.

2. In a circular knitting machine, the arrangement as set forth in claim 1, including second cam means adapted to maintain unselected magnetizable spring members in said mechanically biased condition after the latter have travelled beyond said selection range.

3. In a circular knitting machine, the arrangement as 'set forth in claim 1, wherein said magnetic biasing means comprises a permanent magnet and said electromagnetic means comprises a coil of wire surrounding said permanent magnet and adapted to generate a magnetic field by said control pulse which deactivates said permanent magnet.

4. In a circular knitting machine, the arrangement as set forth in claim 3, wherein the current producing said control pulse is several times larger than the permissible maximum sustained current which said coil of wire can tolerate. 

1. In a circular knitting machine having a rotating cylinder and stationary selection cams, an arrangement for selectively positioning elongated jacks and needles into one of two defined positions so that said jacks may selectively be actuated by cams in a selection range through which said jacks are travelling in response to a control pulse whose duration is short compared to the knitting cycle of the jack and needle, comprising in combination: a magnetizable leaf spring member secured to the lower end of each jack and extending in the direction of the length of the jack when in relaxed condition, the cross-section of the leaf spring amounting to only a small fraction of the cross-section of the jack, the upper end of each jack being pivotally connected to the lower end of an associated knitting needle, first cam means adapted to mechanically bias at each of said magnetizable spring members prior to its arrival at said selection range, stationary magnetic biasing means disposed along said selection range; and being adapted to maintain each of said magnetizable spring members in said mechanically biased condition to cause a coaction between jack and cams of the circular knitting machine; and stationary electromagnetic means disposed along said selection range for selectively counteracting said stationary magnetic biasing means in response to a control pulse to at least partially dissipate the force produced by said stationary magnetic biasing means to allow such selected spring member to move to a mechanically unbiased condition and thereby produce a pivot movement between the jack and needle associated with each selected spring member which causes an interruption of coaction between the respective jack and cams of the circular knitting machine.
 2. In a circular knitting machine, the arrangement as set forth in claim 1, including second cam means adapted to maintain unselected magnetizable spring members in said mechanically biased condition after the latter have travelled beyond said selection range.
 3. In a circular knitting machine, the arrangement as set forth in claim 1, wherein said magnetic biasing means comprises a permanent magnet and said electromagnetic means comprises a coil of wire surrounding said permanent magnet and adapted to generate a magnetic field by said control pulse which deactivates said permanent magnet.
 4. In a circular knitting machine, the arrangement as set forth in claim 3, wherein the current producing said control pulse is several times larger than the permissible maximum sustained current which said coil of wire can tolerate. 